To stay dry for up to 3 hours in a downpour. A helmet can be worn under the hood
Freedom of movement
The cut of the poncho allows you to cover the saddle and ride freely.
It folds down into its own large front pocket.
Fabric is breathable to keep from sweating while riding with the raincoat on.
Very easy to carry in a bag when it's folded into its pouch
A breast pocket is handy on horseback; poncho can also be folded away into it